Pneumatic tool.



PATENTED JULY 14, 1908..

vIl-L Aw WT Cm.. 0T RA `BM Amm H m Y APPLICATION FILED 111111.18, 1907.

. s SHEETS-SHEET '2.

WITNESSES.-

1N VEN TOR. H. A Broc/(way A TTORNE Y. l

No. 893,138.` l PATENTED JULY 14, 190s.

' IH. A. BROCKWAY.

PNEUMATIC' TOOL.

APPLICATION FILED MAB.. 18', 1907.

3 SHEETS-SHEET 3.'

je lO El I4 5 7485586@ 916 e2 ee x6 14 (55 '58- |59 6' n 'o 6a. j .406% 561565 K f EL ,j l WITNESSES: j INVENTOR. W, H. A .B/oc/rway UNITED sTATEs PATENT -o-EEroE.

; HERBERT A; BEocKwAY, oF DENVER, coLoEADoQfV rrnmllwrrc Toor..

Specification of Letterslatnt. i

'Y Patented July 14, 1908.

Application mea nach 1s, V1907. semi Nu. 368,034.

to impinge upon a drillbit or other tool for.

the purpose of drilling holes in rock` or other substances,` to chip, calk orrivet and in short to be of service in all operations requiring a succession of concussive blows. i

The main object of the invention is to provide a valvele'ss pneumatic tool in which the air employed to actuate the hammer or piston is distributed in a manner to insure the derivation of the maximum of efficiency from the minimum of motive power, by varying the pressure of motive fluid which may be opposed to the effective stroke of the piston, so as to render it greatest when the most pressure is needed and least at the'rtimek the least pressureis required.

.Further objects of my invention will be brought out in the *following description,

reference being had to the `accompanying drawings in the various views of which likeI parts are similarly designated and in Which Figure 1 represents a vertical, longitudiv nal section through the device, Fig, 2, an enlarged transverse section taken along a line 2 2, Fig. 1', Figs. 3, 4 and 5 enlarged fragmentary, vertical, longitudinal sections" of the cylinder, hammer and vadjacent parts, illustrating the positions successively as-I sumed by the hammer during theo ration of the device, Fig.A 6 .an enlarge transverse section taken along'l -a line 6 6, Fi 3, Fig. 7 an enlarged transverse section ta en along aline'7l 7 Fig. '/3, Fig. 8- an enlarged cross section taken along a line 8 8, Fig. 1, Fig. Q an enlarged cross lsection along a line 9 9, Fig. 3.

Referring to thev drawings, the reference numeral 2 designates the cylinder, 3v the hammer or piston having a longitudinal reciprocating movement therein, 4 the blocky upon which the hammer or piston impinges during each forward movement, and'5 the chuck designed to hold ythe multilateral drill bit c.' Y

.The cylindrical, longitudinall bore of the barrel 2 which,.in practice, contains the piston 3,. includes four sections or chambers Vdifferent in diameter, the largest one, 7, of

whichis situated at `the extreme, rear end of the cylinder and being designed to receive the air during the return stroke of the piston, may be called the compression and expansion chamber. tion 48 contains and guides the piston head as will hereinafter be described, while the following, further reduced section 9 'is providedl lwith an annular channel 10 which connects by-means of an opening 10a in the cylinder Wall, with an admission pipe 11. A small port 12 furthermore connects the vsaid openlng with the precedingl chamber 8.

The adjolning, reduced sec- The portion of the cylinder adjoining the chamber 9, is counterbored to produce the enlarged Vexhaust chamber 13'which communicates with the atmosplhere by a plurality of radially extendingl ex aust openings 14 1n the cylinder wall. The foremost portion of the cylinder, adjoining the last named chamber is bored to accommodate the striking block 4 and the chuck 5, as will hereinafter be described.

The piston 2, turned to fit the admission chamber 9 of the cylinder, has an enlarged head 15, the diameter of which equals that of rovided interthe chamber-8 and which is mediate its extremities, wit a peripheral,

annular recess 16. central, longitudinal' passage I19, the extremitiesof which comvmunicate respectively, with alateral opening .20 located vin its periphery in proximity to the head 15 and witha slmilar port 21 ad# jacent to its opposite, foremost end. A third port 22 Aextendsfrom the peripheral surface of the foremost 'portion of the piston ,into the passage 19,-` intermediate its 'extremities. l

The proportionate length ofthe various chambers 1n the' cylinder and. parts of the piston as well as the relative location of the several air-ports will bemade apparent dur` ing the description of the operation of the de- 'The cylin` r 2 is provide at itspr'earmost extremity with a socketed head or cap 23 vice, formin part of this s ecification.

surv

having an internal coarse, screw thread shaped in the form of a ratchet tooth, which operatively engages a corresponding, peripheral thread upon the cylinder. A olt 24 extending through a correspondingly formed opening 25 in a'tangential enlar ement of the head, f lrojects into a periphera recess 26. in the cy inder in engagement with a shoulder 27. This arrangement is designed to maintain the two parts in their relative positions, while the shape of. therecess, as shown in Fig. 1() of the drawings, is suchas to permit ad`ustment of the head in case of wear.

}l`he head or cap 23'is ,provided with a sockete'd',y cylindrical, .concentric extension 28 and thewall or partition 29 dividing ythe two sockets has an angular air passage 3() which connects the socket 28afwith a smaller, internally threaded socket 31 in the yeripheral surface of ,the head, into whic projects a coperativelylthreaded nipple on a three way valve 32 by which the air employed to operate the device, is admitted. lhe socket 2-8a is internally threaded to receive and holdv a corres onding art of a handle 33. The handle 33', s own in gig. lof the drawin s, consists Aof-'a yoke 35 terminating ina cy indrical, hollow sleeve 36, Which'in practice, surrounds the socketed extension 28 of the cylinder head. A plunger 42 which is fitted into a bore 39 of'a plug 38 in the socket 28a, is rotatably connected with the yoke 35, and the air admitted through the passageBO, into the socket 28a, forms an -absorptive cushion which by action upon the movable plunger. and the therewith connected handle revents communication to the latter of the jars to which the cylinder is subjected during the o eration of the machine.

A vandle 53 sc'rewediinto an' o ening 54 in the cylinder opposite to the Vbe'ore mentioned socket 31, affords further means to hold and steady the drill during its operation.-

The fronty portion of the cylinder occupied by the striking block 4 has an internal, annular ridge 55 bored to admit the reducedr portion 4a ofthe cylindrical block, the exf tremity of which projects normally into the exhaust chamber 13. f The shoulder 56 produced by the ridge is normally in contact` with the shoulder 57 of the lar er ortion of the block, and a plurality of ra ia y air passages 58 extend at this point through the cy inder wall to communicate with an equal number of/ openings 59 which diverge from a central o ening 60 in the front end of the block. his opening 60 communicates with a longitudinal bore 61 in the drillfbit throu h which, vin ractice, air is conducted to the breast of t e drill hole into which the latter fprojects, as will hereinafter be described.

A The chuck 5 is provided with a peripheral screw thread and secured in the correspondingly threaded mouth of the cylinder in a manner similar to that described for securing the cap 23, a transverse bolt 61 being employed to maintain it in position.

A sleeve 62 provided with an internal, an-

nular recess 63 surrounds that portion of the cylinder which contains the air passages 58' and may be held in either one of two positions by means of Aa spring-actuated dog 64 which being dis osed in a socket in the peripheral surface of t e cylinder, extends in one of two internal grooves 65 in the sleeve.

The recess 63 in the sleeve is connected with the before mentioned air inlet pipe 11, by means of a llexible conduit 66, the flow through which is controlled by a valve or cock 67. When the sleeve is in its rearmost position as shown in Fig. 4 of the drawings, 1ts recess 63 communicates with the exhaust ports 14 leading to the exhaust chamber 13, as well as with the air passages 58 which register with those in the striking block and the air exhausted durin each stroke of the rcciprocating iston, .1s thus conducted into the longitu inal bore of the drill bit 6. When the sleeve is in its other, forward, position, illustrated in Fig.'5, its recessed portion extends only over the radial assages 58 andthe air exhausted through tlie ports 14 is free to pass into the atmosphere.

By opening the valve 67 the recess is brought in communication with the inlet pipe 11, in consequence of which live air is constantl fed into thelongitudinal bore 61 in the dri bit 6. The air thus being introduced into the bore in the rock into which the bit projects, forcibly strikes the breast of the hole and reverberating, carries the chips anddust caused by the action of the drill upon the'rock, out ofthe mouth of the opening and into a rece tacle 68 placed .around the drill bit and hel in engagement with the surface ofthe penetrated Wa by means 'of a coiled spring 69 likewise surrounding the drill bit and engaging the outer end of the chuck 5 and the opposite portion of the rece tacle.

he dust receptacle has been made subject of a separate a lication for patent, Serial $376,012, filed ay 27-1907. Having thus described the mechanical construction of my invention its operation and the advantages derived thereby will now be described.

When the differential area piston is in the rearmost position, as illustrated in Fig. 4, the ports 18 Which'communicate with the central core 17,'4 register with the annular channel 10 'and the compressed air or other motive uid introduced into the said channel through the duct 11, is ree to pass into the compression chamber 7 of the cylinder.

- The piston being situated inthe chamber 8 of the4 cylinder which in diameter corresponds with the head 15, projects with its foremost portion into the'adjoining section 9, the diameter of which equals that of the scales main body of the piston and theannular .space between the peripheral surface ofthe said bodyand the encirclingwall `ol" ,the chamberS, beingL in direct communication 'with' the pressure` supply `b mean-sof the small auxiliary port12, is filled withlive air which `exerting `a pressure upon the shoulder 74 which 'constitutes the smallerV area of the head 15, tends'to movethe piston in a rearwarddirection. thearea of the face' of thc iston vwithin the 'chamber 7., greatly cx?v cee s -that of the shoulder 74, the hammer limpelled by the expansion of thcfluidin the ompression chamber, is moved fonvauily` toY 1`5 impinge upon the, 'striking block 4, which conlirnunicates the blow-'to the juxtaposed too 6.

elastic washer 75 placed between the striking block and the lopposite surface of the chuck 5, limits and mitlg'ates the concussive action ofthe said Kblock upon the chuck and aids in returning 'the forrner'to its norial poe sition.

'Should, by reason of wear ori omission `of the washer, the block 4 remain in the ad#- vanced position so that its rear surface 'ex` tends in a planawithbrbeyond the rear edge of the lannular ridge, 55 and thend f..

the piston is, in consequence, projected .through the exhaustV chamber intothe. portion of the cylinder bore occupied by the chuck, the fact that the said portion corre` spends in diameter with4 the" iston, will cause the formation of anair cus ion to prethe aforesaid shoulder of the ridge 55. .l

The smaller area of the diiferentialpiston is during vits forward movement, ex osedto `the pressure of the air introduced into the chambers 8 and 9 through the duct 12` and the channel 10 until' it` reaches the position illustrated in Fig. 5, when the rear'edge of the circumferential recess, passing the shoulder between the said chambers, cuts off the supply from Ithe channel 10; The port 21of r the conduit 19 has simultaneouslyr `opened into the exhaust chamber 13, causing a par- -tial exhaust of the air which, surrounding the iston, pressed upon the shoulder 74 ofthe 5o -liead, and during further forward movement,

the amount of; air exhausted will be increased as the intermediate port 22 advances beyond-the point 76 into the chamber I13. The result .is that the back pressure., exert-ed upon the smaller area of the head, is grado a ly reduced as the piston advances and the efiiciency of the expandingr air in the lcharn-` ber 7 is proportionately increased.

When the piston reaches its foremost position, thegreater part-of the -air contained in the e pans'ion chamber 7, is exhausted through the ports 18 which now open into the e haust chamber and as the air-supply has continuously remained in communicaas. tion with the space between the piston body` the pressure upon .they

vent the piston from'coming in contact withat the terminationl of the said movement.

and the Wall of the piston chamber 8, the i `pressure upon the shoulder 74 of the head exceeding that of its rear face will impel the pistonin rearward direction:

-' During the return stroke 'of the piston the pprts 21 and 22 of the channel 19 perform a j nction opposite to that accomplished durn ing the forward movement or I with 'other words, when the ports 22 and 21 pass successively beyond the vshoulder76 between the vchambers .13 and 9, the exhaust of the air surrounding the piston will be raduall decreased and the ressure upon te shou der 74 ofthe hea( be proportionately in-' creased, which pressure is further augmented through instrumentalit of the annular recess 16 in the iston, t e rear end of which extends beyondthe shoulder'77ybetween the chambers 9 and 8', when the front endof the pistonlpasses out of the exhaust chamber and by connect-ingthe air space around the ,cylinder with the channel 10,. causes the full' towards the strikin block .to be greatest `when the blow' Whic actuatesthe tool, is

delivered and that duringthe 'return' stroke animer -head increases in proportion to thedistance traveled land-the constantly increasing degree of compressoin ofthe remaining air in the expansion chamber 7. It will be understoodl .that the number of intermediate ports between vthe terminal ports 20 ,and 21 of the 'assage'19 inthe piston, may be increased to rther graduate the exhaust from' the space between the piston 'and the wall of chamber 8, and that to insure effective operation of' the im roved device, .the combined areas of the oriEices of the 'exhaust ports leading from 'the said passage, should at no time exceed the area ofthe yauxiliary inlet port 12. `It should` furthermore be observed that the seeming disadvantage of a minimum of pressure at the beginning of the return stroke, is fully oiisetby the actionl of the rebounding striking block upon the piston.

" Havingthus'described my invention what 115 vI claim is 1. In a valveless pneumatic tool, a cylinder, a piston fitted for reciprocation "therein, the said cylinder and piston having lco erative means for continuously directing uid pressure against a facefof the piston, 1n opposition toits forward movement, and means n to cause variation of the said pressure so as to render it greatest at the 'beginning and least 2. In a valveless pneumatic tool, a cylinder having pressure supply and exhaust ducts, a piston fitted for reciproc'ation therein, the said cylinder `and piston having cooperative means for continuously directing 130 motive fluid from the supply port against a face of the piston, in opposition to its forward movement and means to direct part of the said fluid to theexhaust port during the latter part of the said movement.

3. In a pneumatic tool, a cylinder having pressure supply and exhaust ducts, a differential piston fitted for reciprocation therein, means to maintain continuous communication between the supply duct and a face of the said piston and means to cause reduction of the pressure upon the said face during the latter part of the forward stroke of the piston.

4. In a pneumatic tool, a cylinder having pressure supply and exhaust ducts, a differential piston fitted therein for reciproca-tion by pressure of the motive fluid upon its working faces, and means to cause discharge of motive fluid from the said faces d-uring the latter part of the forwardstroke of the piston.

5. In a pneumatic tool, a barrel bored. to form successively arranged iston, admission and exhaust chambers of di erent diameters, and'having ya pressure supply duct opening in the admission chamber and an auxiliary, smaller. pressure supply duct communicating with the piston chamber, a reciprocating differential iston having an enlarged 30 head fitted in t e piston chamber and a smaller body portion fitted in the admission chamber, the said body being formed with interconnected, peripheral ports located so that one Will continuously open into the pis- 35 ton chamber during the movement of the hammer while the other opens into the exhaust chamber during the second half of the forward stroke.

6. In a pneumatic tool, a barrel bored to form successively arranged iston, admission and exhaust chambers of di erent diameters, and having a pressure supply duct opening in the admission chamber and an auxiliary, smaller pressure su ply duct communicatinwith the piston e amber, a reciprocating, di erential piston having an enlarged head fitted in the lpiston chamber and a smaller body portion fitted in the admission chamber, the said body being formed with an internal passage, a port eading therefrom to the periphery of the hammer in proximity to its head and a series of successivel arranged, similar port's at its foremost end', the said ports being located so that the said se.- ries will open in the exhaust chamber when the piston has reached its foremost osition.

7. In a pneumatic tool, a barrel cred to form successively arranged piston, admission and exhaust chambers of different diameters and having a pressure supply duct opening in the admission chamber and an auxiliary, smaller pressure supply duct communicating with the iston c amber, a reciprocating, differenta piston having an enlarged head et fittedin the piston chamber and a smaller body portion fitted in the admission chamber, the said body bein formed with an internal passage, a ort iiaading therefrom to the periphery of t ie iston in proximity to its head and a sciies o successively arranged, similar ports at its foremost end, the ports comprised in the said series being located so they will o en in 4the exhaust chamber when the piston as reached its lforemost position, while the combined areas of their orifices is less than the area of the auxiliary supply duct.

8. In a penumatic tool, a barrel bored to form successively arranged piston, admissimi and exhaust chambers of different diameters 30 and having apressure supply duct opening in the admission chamber and an auxiliary, smaller pressure su ply duct communicat ing with the iston cfiamber, a reciprocating, differentia piston having an enlarged head S5 fitted in the piston chamber and a smaller body portion fitted in the admission chamber, the said body being formed with intcrconnected, peripheral ports located so that, one will continuously open into thc piston chamber during the movement of the hainmer, while the other opens into the exhaust chamber during the second half of the for ward stroke, and with a circumferential recess so located that during the forward stroke of the piston it will establish communication between the piston and admission chambers until. the port adjacent the foremost end of the piston has opened into the exhaust chamber.

9.A In a pneumatic tool, a cylinder having a main su ply duct and a smaller auxiliary duct leading therefrom, and -a differential area piston fitted for reclprocation therein. and having a circumferential recess so lo- 11).". cated as to establish communication between both supply duets and its smaller area during the first part of its effective .stroke and between the said are'a and the auxiliary pori only, during the latter part of the said st rokc. 1l@

10. In a pneumatic tool, in combination a cylinder formed with` successivel Y arranged piston, admission and exhaust c iambcrs of different diameters, a here at its front end to receive a striking block and a recess iu- 11;', terinediaterthe said bore and the exhaust chamber, and of a diameter equal to that of the admission chamber, a striking block within the bore, normally projecting into the recess, a differential piston having im enlarged head fitted in the iston chamber and a smaller body ortion ttcd in thc admission chamber an l)having interconnected, peripheral lpoi'ts so located that one opens continuous y into the iston chamber, .while the foremost one is c osed by engagement with the wall of the recess during excessive forward movement of the former.

11. In a pneumatic tool, a cylinder having main supply and exhaust ducts und it smailcr if. n

vform successively arranged p1ston,'adm1s and an auxiliary duct opening into the pis-v auxiliary duct leading from the former, .and adiiierential area `piston fitted for reciprocation therein, the said cylinder and piston 1 having coperative means to establish, during its movement, intermittent communication between the smaller area of the iston head and the main supply. duct an continuous communication between the said area and the auxiliary duct, and the said piston having means which, in coperation with the said exhaust ducts, willl cause discharge of part of the motive Huid' pressing upon the said area, during the latter part of its movement in one direction.v 12. I'n a pneumatic tool,l a barrel bored to sion and exhaust chambers of different diameters and vhaving a pressure supply duct opening in the admission-chamber and an auxiliary, smaller communicating with t e pistone amber, a reciprocating, diierential piston having an enlarged headtted in the iston chamber and a smaller body portion tted in 'ahead-v mission chamber, ,the said piston being adapted to maintain communication of both the supply ducts with the smaller areaof its head during the iirst part of its 'forwardl stroke and of the auxiliary one onlyduring the completion of the stroke. ,v

13. In a pneumatic tool, thecombination of a cylinder bored to form successively arranged piston, admission and exhaust chambers of different diameters and -having an annular channel in the admission chamber, a supply duct opening in the said channel ton chamber, a differential piston having an enlargedhead fitted in the4 iston 4chamber and a smaller body portion tted in the ad mission lchamber and having. eri heralports in communication elsarger area otitis head and normallyfregisterlg with the said channel.

14. In a pneumatic tool, a body:memberv having a threaded extremity, a coperatively threaded lmember Vin engagement therewith, `the exterior member having an opening axially in tangential relation vto its threaded surface and the interior member having a shoulder formed by ade ression in its periphery, and a locking mem er, longiressure4 su ply duct i the last part of its forward and the first tudinally movable in the `said opening and adapted to engagel thesaid shoulder when ,the parts arein their relative positions.

15. In -a pneumatic tool a barrel bored to form successively arranged piston, admissio'n and exhaust chambers of different diameters and provided with-'a series -of pressure supply ducts, a reciprocating differential piston having l.an enlarged head fitted in the piston ychamber and a smaller body ortion fitted in theadmission chainber, te said piston having means to establish simultaneous communication of the said pressure supplyv ducts with the smaller area of its head while theiirst part of its forward and in the last part of tsreturn strokel 4and continuous communication of i one of the said supply ducts with the 'with chambers common thereto, and having principal and auxiliary pressure supply ducts, a reciprocating differential area piston fitted 'insaid `barrel and having means to establish in coperation with relative means on the cylindencommunication of the auxiliaryl l,pressure-supply duct with the smaller' area of its head during its entire forward stroke,-l

and to exhaust part of the motive fluid exerting pressure upon the said area, during the last part of its forward andthe first part of its return stroke.4

In testimony-whereof I have affixed my signature in presence of two witnesses.

4 vHEBERT A. BROCKWAY.

`Witnesses:

' G; J. ROLLANDET.,

K. M. STUMP. 

